- 2024–
EveryNow
Head of Evals, after a stint leading AI tech consulting, and author of the Also True for Humans column.
Head of Evals
Aug 2026 – Present · 3 mos
Working across teams to help people build personal benchmarks for evaluating new models from the major AI labs, and teaching agents to build up knowledge of their users so they get better over time.
Head of AI Tech Consulting
Jan 2026 – Aug 2026 · 8 mos
Led AI consulting engagements with technology teams: designed training, delivered client work and collaborated with the major research labs.
Columnist, Also True for Humans
2024 – Present
- 2024–
O’Reilly MediaNow
Author of two books on building reliable systems with language models.
Author, Context Engineering with DSPy
Oct 2025 – Present · 1 yr 1 mo
A second book: self-optimizing prompt pipelines for building reliable AI agents with DSPy.
Co-author, Prompt Engineering for Generative AI
Jun 2024 – Mar 2025 · 10 mos
A guide to prompting LLMs and diffusion models, written with James Phoenix, including the code and notebooks.
- 2022–
Marketing MemeticsNow
A book on creative testing.
Author
Jan 2022 – Present · 4 yrs 10 mos
How to break campaigns into their components, test them and reuse what works.
- 2020–
VexpowerNow
Simulator-based courses for data-driven marketers who want to be more technical.
Co-founder
Oct 2020 – Present · 6 yrs 1 mo
Courses on creative testing, marketing mix modeling, RFM analysis, pricing strategy and media optimization.
- 2025
Ask Rally
Co-founder of Rally, an AI persona tool for synthetic market research: simulated audiences calibrated against real people.
Co-founder
Jan 2025 – Dec 2025 · 1 yr
Built the first prototype and ran R&D and evals, using DSPy to calibrate personas. Scaled to 5,000 parallel persona queries for enterprise projects, and grew to 6,000 users and 200 paying customers.
- 2020–25
Saxifrage
A holding company for growth experiments and products, including Vexpower, and these days a lab for AI evals and prompt optimization.
AI Engineer
Jun 2020 – Dec 2025 · 5 yrs 7 mos
Solo consulting: prompt engineering experiments with models from OpenAI, Anthropic, Google and open source, either hands-on in notebooks or embedded in a client’s engineering team. Also behind Vexpower and the Complete Prompt Engineering Bootcamp on Udemy.
- 2022–23
Recast
Wrote about marketing mix modeling, incrementality testing and measurement for Recast’s blog.
Contributing writer
2022 – 2023
- 2014–20
Ladder
Co-founded a growth marketing agency that grew to 50 people in three countries and ran thousands of experiments for clients.
Co-founder and COO
Aug 2014 – Mar 2020 · 5 yrs 8 mos
Helped grow over 200 clients across the major digital channels, with a team across the US, UK and EU.
- 2015
Sumo Group
SumoMe.com and AppSumo.com.
Marketing Sumo
Aug 2015 – Nov 2015 · 4 mos
Ran paid user acquisition to grow the install base.
- 2013–14
ShopStyle by POPSUGAR
Fashion shopping search.
Digital Marketing Manager
Dec 2013 – Sep 2014 · 10 mos
Owned UK marketing strategy across paid search, SEO, email and other channels.
- 2011–13
Travelzoo
Travel deals publisher.
Associate Product Manager, Marketing
Apr 2013 – Dec 2013 · 9 mos
Coordinated marketing product requirements across North America and Europe.
Marketing Executive
Sep 2011 – Apr 2013 · 1 yr 8 mos
Led subscriber acquisition and paid search.
- 2010–11
Efficient Frontier
Search advertising management platform.
Associate Account Manager
Jun 2010 – Sep 2011 · 1 yr 4 mos
Client-facing analysis and strategy for online advertisers.
- 2009–10
Travelex
Foreign exchange.
Client Manager
Oct 2009 – Jun 2010 · 9 mos
Client retention and reactivation.
- 2009
Department for Work and Pensions
UK government.
Economist (Intern)
Jun 2009 – Sep 2009 · 4 mos
